Joe Rolston argued the cause for appellant. With him on the brief were Conrad C. Mount, O. R. Stites and Mark H. Adams.

Solicitor General Rankin argued the cause for the Federal Power Commission, as amicus curiae, urging reversal. With him on the brief were Assistant Attorney General Doub, Paul A. Sweeney, Robert S. Green, Willard W. Gatchell and Howard E. Wahrenbrock.

Dale M. Stucky and Frank G. Theis argued the cause for appellees. With them on the brief was Clyde Milligan.